为研究内蒙古三种类型的温带草原即荒漠草原、典型草原和草甸草原生态化学计量特征及其对环境因子的响应，本研究在内蒙古三种草原上选择具有代表性的样地，采用野外刈割法采集植物地上部分样品、钻土芯法采集植物细根样品，并于室内检测不同植物地下部分（即细根）和地上部分（即叶和茎）N、P化学计量，检测结果通过统计方法，分析温带草原植物不同器官间N、P化学计量特征的关联；研究不同生境下温带草原植物N、P化学计量特征与环境因子的关系，阐明气候变化和土壤环境差异对草原群落的影响。其结果对揭示草地植物与环境的关系、草地植物生物的进化道路和适应生境途径等问题的机理有着重要意义。研究结果如下：（1）内蒙古草原植物地上部分平均N含量27.4mg/g、P含量2.0mg/g、N/P比为14.0；植物细根平均N含量10.4mg/g、P含量0.7mg/g、N/P比为15.9。（2）细根N含量小于地上部分N含量；三种草原类型中N含量依次为荒漠草原（12.2mg/g），典型草原（10.0mg/g），草甸草原（8.8mg/g），无显著差异。细根P含量明显低于地上部分P含量，三种草原类型中P含量依次为荒漠草原（0.8mg/g），典型草原（0.7mg/g），草甸草原（0.6mg/g），也无显著差异。而细根N/P比与地上部分N/P比相近，三种草原类型中N/P依次为荒漠草原（15.5），典型草原（16.0），草甸草原（16.3）。（3）地上部分和细根自身的P和N/P含量均呈现显著相关性，且成负相关；而N和P在地上水平上有较显著正相关性，N和N/P在细根水平上有较显著相关性；而地上水平的N和N/P、细根水平的P和N/P含量均无显著相关性。地上部分N含量随着地上部分P含量的增加而上升；相应的，地上部分N/P比却随着地上部分P含量的增加而降低。（4）不同植物器官组织间，对于N、P的分配具有显著的相关性。随着地上部分特定化学元素含量的增加，细根相应化学元素也随之增加，说明地上部分和细根吸收和利用营养元素的比例具有一致性。（5）在地上部分和细根水平上N、P、N/P与气象因子之间均不存在显著相关性，但与土壤因子有一定得相关性，其中，土壤N对植物地上部分和细根的元素的积累均有着明显的影响。从整体来看，细根中元素与土壤中元素的含量相关性较大，与土壤容重、土壤pH均无显著相关性；而地上部分中除N以外，各元素与土壤各指标相关性均不大。由于内蒙古草原地区各部分群落组成差异大，环境因子间组合状况复杂，因此，扩大研究范围、增大研究的空间尺度对今后的研究很有必要，如适当增加高寒地区样地（包括高寒草原，高寒草甸）等。将来的研究应考虑植物种类、物种多样性等生物因素，以进一步了解草地生态系统的生态化学计量学特征的分配与响应机理。

To study ecological stoichiometry characteristics and their response to environmental factors of three types of temperate grasslands in Inner Mongolia (desert steppe , typical steppe and meadow steppe)，the study selected representative samples of three types of the grasslands in Inner Mongolia. The study collect above ground plant parts by wild mow cutting samples, and collect samples of fine roots of plants by drill cores. By testing N, P stoichiometry of different underground parts of the plant ( ie fine roots ) and aerial parts ( ie, leaves and stems ) and using statistical methods, this work analyze the association of N, P stoichiometric characteristics between different organs of temperate grassland plants and the relationship N, P stoichiometric characteristics and environmental factors in different habitats of temperate grassland plants. Then this study clarify the effects of climate change and soil environmental differences on grassland communities. The result has an important significance to reveal the relationship between the grass plants and the environment, and the evolutionary mechanisms and adaption to the habitat o f grass pants.The results were as follows:( 1 ) In Inner Mongolia grassland, the average N, P content of aerial parts are 27.4mg / g and 2.0mg / g, and N / P ratio is 14.0 ; plant N, P content of fine root is 10.4mg / g and 0.7mg / g, and N / P ratio is 15.9.( 2 ) The N content of fine root is less than that in aerial parts. The N content is 12.2mg / g in desert steppe, 10.0mg / g in typical steppe, 8.8mg / g in meadow steppe, and there is no significant differences between three grassland types. The P content of fine root was significantly lower than that in leaves, P content is 0.8mg / g in desert steppe, 0.7mg / g in typical steppe, 0.6mg / g in meadow steppe, and there is no significant differences between three grassland types. The N / P ratio of fine root and leaf is similar, followed by 15.5 in desert steppe, 16.0 in typical steppe, 16.3 in meadow steppe.( 3 ) P and N/P levels in aerial parts and fine roots showed a significant negative correlation, and N and P in the aerial parts level show significant positive correlation. N and N / P in the fine roots level have significant correlation, while N and N / P level aerial parts and that in fine roots were not significantly correlated. With the increase of nitrogen content in aerial parts, phosphorus content rises; conversely, with the increase of the phosphorus content in aerial parts, the nitrogen and phosphorus ratio is reduced .( 4 ) Among different plant organs, the distribution of N, P has a significant correlation. With the increase of aerial parts specific chemical element content, chemical elements corresponding fine roots also increased, indicating that the proportion of absorption and utilization of nutrients in aerial parts and fine root is consistency.( 5 ) On the level of aerial parts and fine roots, the N, P content, N / P ratio and meteorological factors have no significant correlation, while there was some correlation with soil factors. The soil N have a significant impact on plant aerial parts and fine roots accumulation. Overall, the content of elements in fine roots has a greater correlation with soil elements, while it is not significant correlated with soil bulk density and soil pH; while except N in the leaves, other elements are not correlated with soil.In aerial parts and fine roots, there is no significant correlation between the level of N, P, N/P and meteorological factors, but certain correlation with soil factors. The accumulation of soil available N on plant aerial parts and the fine roots has a significant impact. On the whole, the element content of fine root has stronger correlation with the element in soil, but no correlations with soil bulk density and soil pH . There is no significant correlations with soil factors in the aerial parts except element N in the leaves.Owing to the large difference of each part of the community composition of Inner Mongolia grassland area and the complex of environmental factor combination condition, the Spread size of the research scope is necessary for the future research, such as increasing the cold area (including alpine steppe, alpine meadow) appropriately. Biological factors, such as plant species and species diversity should be considered in future research, in order to understand the ecological stoichiometry of grassland ecosystem characteristics and the distribution of the response mechanism further more.